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https://issues.apache.org/jira/browse/ZOOKEEPER-2076?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14231958#comment-14231958
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Hongchao Deng commented on ZOOKEEPER-2076:
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My understanding is that leader election will take a long time regardless how
close followers are:
1. Leader will take a snapshot on lead():
https://github.com/apache/zookeeper/blob/trunk/src/java/main/org/apache/zookeeper/server/quorum/Leader.java#L418-418
2. Learner will take a snapshot on receiving NEWLEADER:
https://github.com/fengjingchao/zookeeper/blob/trunk/src/java/main/org/apache/zookeeper/server/quorum/Learner.java#L486-486
While the first one is unnecessary, the second one is introducing bugs... I see
the best solution is to fix the problem of taking snapshot. But it's out of the
scope here.
Any idea on exposing the API of suggestedLeader?
> Improve Leader Change Mechanism
> -------------------------------
>
> Key: ZOOKEEPER-2076
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2076
> Project: ZooKeeper
> Issue Type: Improvement
> Components: server
> Affects Versions: 3.5.0
> Reporter: Alexander Shraer
>
> When a leader is removed during a reconfiguration, ZOOKEEPER-107 uses a
> mechanism where the old leader nominates the new one. Although it reduces the
> time for a new leader to be elected, it still takes too long. This JIRA is
> for two things:
> 1. Improve the mechanism, e.g., avoid loading snapshots, etc. during the
> handoff.
> 2. Make it a first-class citizen & export it as a client API. We get
> questions about this once in a while - how do I cause a different leader to
> be elected ? Currently the response is either kill or reconfigure the current
> leader.
> Any one interested to work on this ?
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